The present invention relates to an acoustically decoupled underbody and passenger compartment for a motor vehicle and, more particularly, to an underbody having improved crash resistance as well as acoustic isolation of the passenger compartment.
German Offenlegungschrift No. 2,145,467 discloses a motor vehicle having a pair of side rails, a pair of sills displaced outwardly from the side rails and running parallel to them, and a floor panel having inclined front regions. Each of the side rails has an inclined portion toward the front with a provision for spacing them from the inclined front regions of the floor panel to provide acoustic decoupling of the passenger compartment.
Except for torsion pads provided between the front ends of the sills and the side rails, the sills are supported from the side rails essentially only in the area of their rear end regions. This support is by way of a transverse connection between the side rails and the floor panel. It is well known that vibrations coming from the front of the car may lead to the development of disturbing noises and rattles in the passenger compartment. Because a space is maintained between the side rails and the floor panel, direct transfer of vibration from the front of the vehicle containing the engine is avoided in order to minimize noise and rattles in the passenger compartment.